Why you ask for cheapest altcoin? Cheap price is not mean to be able to grow very much. It is depend on their market cap and their technology like you buy Kin (1 KIN = $0.000120 ) now. This is very cheap price but circulating supply is 756,097,560,976 KIN. Now market Cap is $90,543,793 and will more in the future(Total Supply is 10,000,000,000,000 KIN). It is not easy to hit market cap $109,124,311,643 like Bitcoin or $1,373,798,438 like Tron. If someone want to buy cheap price altcoin I think he should think about market cap plus technology